Maharashtra Board Class 4 EVS Chapter 23 Natural Disasters PDF Download

Natural Disasters

Many a time, we hear of serious mishaps. An earthquake happens here, a flood occurs somewhere else. A storm occurs in one place, another place is struck by lightning. There can be a landslide or a hailstorm.

In these incidents, several people are injured. Some even lose their lives. Houses collapse. Animals die. Standing crops get destroyed. There is great damage to property. Day to day life is disturbed. It takes several days for life to get back to normal.

A New Term

Disaster: a very serious mishap. One in which people or animals can get injured or die. Crops and other property is destroyed. Houses collapse.

Can You Tell?

Which frightening natural events can be seen in the pictures below?

Sometimes during the rainy season, suddenly there is a downpour which lasts for two or three days. The river flows in full spate. It may even overflow its banks and enter nearby settlements. What is the name given to such a rise in the level of river water?

Name two places in Maharashtra where earthquakes have occurred.

An earthquake under the sea gives rise to very high waves. What are these gigantic waves called?

Teacher's Note

In India, during monsoon season, heavy rain often floods villages. This is a natural disaster that we must be ready to handle. Always keep high ground safe when rains come.

Exam Trick

Remember: Flood = too much water. Drought = no water. Just like too much sugar in tea is bad and no sugar is also bad, both are bad for crops!

Points to Remember

A disaster is a serious event that hurts people and destroys homes.

Earthquakes, floods, and storms are natural disasters.

We cannot stop natural disasters, but we can be ready for them.

Many people lose their lives and homes in natural disasters.

These and some other mishaps have natural causes. They are called natural disasters. We do not have enough knowledge about when and where they might happen. And it is impossible for us to prevent them. We must not get frightened by such disasters. Instead, it is more useful to find out how to face such a disaster if it happens.

Untimely Rains

In our country, we get rains only in a certain period of the year. In Maharashtra, it rains in the months of June, July, August and September. This period is called the monsoon or the rainy season.

In Maharashtra, on some day before the start of the rainy season, the sky suddenly gets overcast. There is lightning and thunder. It rains heavily for a short while. These are called pre-monsoon showers.

However, when it rains at other times besides the monsoon or pre-monsoon period, such rain is said to be untimely rain.

Untimely rain comes without warning, when we least expect it. People who have left their houses without umbrellas and raincoats have to run helter-skelter for shelter. Or, they have to get soaked in the rain.

But, untimely rains can also cause serious damage. People grow winter crops. Occasional, light showers are good for this crop. But if it rains too much, fields get water-logged. And the crop may rot causing much loss.

Often, a hailstorm accompanies with untimely rains. Severe hail causes injuries to people and animals. It shatters roof tiles. It can damage crops in fields and fruits in orchards.

If mango trees are in blossom at that time, the blossoms may rot or fall off. This leads to a fall in mango production.

Teacher's Note

In some parts of India, sudden hail can destroy an entire mango harvest in one day. This is why farmers worry about untimely rain during flowering season.

Exam Trick

Remember: Untimely rain = rain at wrong time. Just like eating your lunch at midnight is untimely, rain in winter is also untimely and bad!

Points to Remember

Monsoon rains come in June to September in Maharashtra.

Untimely rain comes at the wrong time and damages crops.

Hailstorms with untimely rain can hurt people and animals.

Hail can break roofs and destroy fruit trees.

Floods

Sometimes during the monsoons, it rains heavily and continuously for three or four days. This causes the level of water in a river to rise. That is, the river gets flooded. If it does not stop raining, settlements on its banks can also get flooded.

Mud houses on the riversides collapse during a flood. People and animals may die due to drowning. Flooding of settlements causes problems in everyday life.

At such times, we should go to a safe place at a height and come back only when the flood waters recede.

The current of flood waters is very strong. It is dangerous to swim in flood waters.

Earthquakes

Sometimes, the rocks in the bowels of the earth move. As a result, waves are produced in the layers of rock.

If a stone is thrown into a pool of still water, we see circular ripples around it. They move to the edges of the pool. After some time, the waves settle and the water becomes still as before.

Exactly the same kind of waves are produced inside the earth. For a few seconds, the ground shakes. That is the earthquake. Then everything quietens down again. Where the earthquake occurs, buildings are shaken. Things inside the house all fall from their places. Houses that are not strong enough, simply collapse into heaps. People get trapped under the heaps and get injured or even lose their life. The most damage occurs near the centre of the earthquake. An earthquake also causes injuries or death of animals we keep.

Teacher's Note

Many cities in India like Delhi, Assam, and Gujarat have experienced big earthquakes. We must know how to be safe during earthquakes by staying under tables or in doorframes.

Exam Trick

Remember: Earthquake waves = ripples in earth like ripples in water. Just like you hide under a bed when lightning comes, hide under a table when earthquake comes!

Points to Remember

Earthquakes happen when rocks inside the earth move.

Earthquakes shake the ground and last only a few seconds.

Houses can collapse and people get trapped during earthquakes.

During an earthquake, sit under a table or stand in a doorframe to stay safe.

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